1. Field of the Invention
The present invention is directed to improved welding systems particularly adapted for use in gas metal arc welding (GMAW) which is commonly referred to in the industry as "MIG" type welding. The term MIG stands for the metal inert gas where the inert gas is forced through the front end of the welding gun to provide a surrounding layer or blanket of inert gas to protect the molten welding puddle. The inert gas is typically a combination of various gases such as argon, carbon dioxide and oxygen.
There are a number of various types of MIG welding systems currently available. These MIG welding systems include specifically "push-pull" or "spool guns", "smoke extraction" or "smoke guns", "water cooled guns" or "air cooled guns" or variations of each type of gun that have particular features which are preferred for use with certain materials or in certain welding situations. In addition to the common use of inert gases, the MIG welding systems also utilize continuous welding wire which may be rolled onto a spool and fed through a coaxial welding cable to the welding gun or fed through the gun from a spool mounted on the gun. Because of the continuous welding wire, MIG welding systems are generally faster than tungsten inert gas (TIG) systems or conventional stick welding systems which utilize individual welding rods.
2. Description of the Prior Art
MIG welding systems have been widely used in the United States and other places around the world since at least the 1960's. The present invention is directed to a number of improvements in conventional welding systems and more particularly in improvements in MIG welding systems such as spool guns and smoke extraction or smoke guns.
Spool guns are a specialized type of MIG welding system where a spool of wire is mounted on or near the gun portion of the welding system rather than near the power source as in conventional MIG welding systems. Spool guns are particularly suited for use in situations where the welding wire is aluminum and/or it is desirable to have a welding cable of twenty-five feet or more. One such area of use is in the construction or repair industry where the power source may be mounted on a truck or other movable platform where the welding surface may not be conveniently located within the 10 or 15 foot radius commonly necessary to use a conventional MIG welding system.
Smoke extraction or smoke guns are another specialized type of MIG welding system which is particularly suited for welding in confined areas or where galvanized metals are used. A smoke gun allows the user to draw the smoke which is created by the welding process through the welding system by a vacuum system which filters the welding fumes to remove the particulate matter therefrom, thereby reducing the exposure of the operator to the smoke.
One of the difficulties with many of the currently available MIG welding systems relates to the handle and conductor tube of the welding assembly. In welding, it is imperative that the welder be able to provide a durable weld between varied materials in a variety of situations. This can only be accomplished with consistent and steady movement of the welding gun across the materials which are being welded. In many situations, the welder is required to make the same weld repeatedly at awkward or inconvenient angles. In other situations, the welder may be required to make durable and consistent welds at varied angles and orientations to the materials to be welded.
It is extremely difficult to provide a consistent weld with many of the currently available systems which utilize a straight handle because the handle may be awkward to grasp for long periods of time and may also include a conductor tube which is oriented at a fixed angle to the gun. With repetitive welding, the welders hands and arms may tire due to the difficulty of gripping the handle at the same orientation for an extended period of time to actuate the trigger on the gun. When the welder is required to weld at a variety of angles, the welder must hold the gun at a variety of potentially awkward angles to their body to properly align the gun with the materials to be welded thereby contributing to the fatigue of the welder.
Therefore, it is important to provide a handle for a welding gun which is relatively convenient to grasp for extended periods of time. Additionally, it is important to provide a conductor tube which may be readily articulated and rotated with respect to the handle to allow the welder to periodically change their hand and/or arm orientation with respect to the materials being welded.
In addition to reducing the efficiency of the welder by increasing the fatigue of the welder, currently available welding systems also utilize welding contact tips and gas diffusers which are referred to in the industry as consumables because they must be periodically replaced. Therefore, in addition to the cost of repeatedly replacing the contact tip and/or gas diffuser on the welding guns, there is a further cost to the employer when the welder spends time replacing contact tips and/or gas diffusers rather than producing the product.
Those skilled in the art will recognize that the welding process produces a lot of heat. In order to melt the welding wire, the arc point will sometimes reach 10,000 degrees F. (5,537 degrees C.) or more. Even though the molten pool of metal beneath the arc point is typically cooler, the molten pool of metal may reach 5,000 degree F. (2,760 degrees C.) or more. The contact tip is typically less than one inch (2.54 cm.) above the arc point and conventional contact tips may operate at temperatures of approximately 1,500 degrees F. (815 degrees C.). In the industry, contact tips are typically formed from various copper alloys which soften as the operating temperature increases. Contact tips are subject to internal wear because the welding wire is fed through the interior thereof at a time when the contact tip is softened due to elevated operating temperatures.
The present invention also increases the efficiency of the welder by providing improved contact tips and/or gas diffusers which are more durable than currently available consumable components and therefore need not be replaced as often as in prior welding systems.